No offense but no it is not common sense. The economics of monopolies have been studied for centuries, including any benefit from standardization (like with Standard Oil). It creates a costly deadweight loss.
For what it’s worth I was there, and the handful of OSes in the 1980s (not 20) weren’t as problematic as the monopoly later. It seems like common sense to me that today’s multiple browsers are better than IE standardization was.